Train control



- W. K. HOWE TRAIN CONTROL Original Filed pril 5, 1919 y 7%KENTOR. I

- A'TT RNEY Patented Jan 27, 1925. 5

UNITED STATES PATENT OFFIC.

WIN'IHROP K. HOV] E, OF ROCHESTER, NEW YORK, ASSIGN'OR TO GENERAL RAILWAY fiIGNAL coMrAuY,

OF GATES, NEW YORK, A GOBlORATION OF NEW YORK.

TRAIN CONTROL.

Original application filed April 3, 1919, Serial No. 287.132. Divided and this application filed March 10,

To all whom it may concern:

Be it known that I, VVINTHRO]? K. HOWE, a citizen of the United States of America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Train Controls, of which the following is a specification.

This invention relates to automatic train control systems, and more particularly to the means for communicating from the track to the train the necessary and proper controlling influences.

One of the essential features of any system of train control is an efficient and re liable means for establishing communication between the train control apparatus on the locomotive, or control means therefor, and the traffic controlled elements along the track, which are subject to control by the presence of other trains or dangerous conditions ahead, such that the necessary controlling impulses or influences required to control the operation of the train control apparatus on the locomotive may be effec tively transmitted whenever dangerous con ditions demand. Such means of communication between the track and a train should, it is believed, be one which acts inductively, that is, without any physical contact between any parts on the track and any parts on the train; and one of the principal objects of this invention is to provide a simple and reliable construction and arrangement of parts capable of transmitting controlling influences by electro-magnetic induction in such a way that the operation of the system will not be affected by weather conditions and can be arranged to operate satisfactorily with various clearances, types of rolling stock, and other practical working conditions.

In communicating from the track to the train inductively, it is believed expedient to employ as a track device an inert magnetic element, that is, a magnetic body which does not require electrical energy to maintain it in its active or its inactive condition. One form of train control apparatus to cooperate with an inert track element of this type comprises a core of suitable iron having a magnetizing winding and having suitable electro-responsive devices associated therewith, whereby when this core passes over Serial No. 62 ,250,

an inert track element along the track comprlsing a dead mass of magnetic material when 111 its active condition, the track element will change the flux through the magnetic circuit of the car element on the vehicle, thereby inducing an electro-motiveforce which will affect the electro-responsive device associated therewith.

In order to make this inert track element ineffective to produce operation of said electro-responsive device, a winding is provided on the track element which may be closed upon itself by suitable controlling devices whereby a choking effect is produced-by the winding. When a magnetized car element: passes over. the track element with its winding closed upon itself, the flux through the magnetic core of the car element will not be changed appreciably, that is, a very slight change of flux through the track element will induce a current in the track element winding causing a magneto-motiveforce which will counteract the magnetomotive-force of the car-carried element, in consequence of which very little magnetism will link the two elements, and the electroresponsive device on the train will not be operated.

The advai'itage of an inductive communicating system of this kind is that no source of electrical energy is required for each track element along the track resulting in economy, especially when primary batteries are used, and which makes a device which operates on the side of safety because an open circuit in the winding will cause an automatic actuation of the apparatus carried on the train, whereby the train will be controlled. ()ne of the disadvantages and difficulties of an inductive communicating system of this kind is the effect produced on the car-carried devices by other. magnetic bodies, such as crossing rails, switch frogs, or the like, which produce a similar action on the train carried element, and although feeble, may under certain. conditions cause automatic control of the train. For convenience, the effect of such foreign magnetic bodies along the track will be referred to as rail interferences throughout this specification.

With the above and other considerations in mind, the principal object and purpose of the present invention contemplates the provision of means'to prevent such magnetic bodies (crossing rails, and the like) from causing a sudden change of flux through the train carried element, as the train moves over such bodies. More specifically, it is proposed to build gradually sloping approaches of magnetic material adjacentsuch magnetic bodies, and in the path of the train carried element so that the change of flux will be very gradual, and therefore the voltage indnced in the train carried elementwill be correspondingly low and toosmall to prodnre the effect of a control influence when a train passes over such magnetic bodies and the approaches thereto.

Other specific objectsiand features of this invention will. appear hereinafter as the description progresses, and thenovel features of the invention will be pointed out in the appended claims.

For thepurp'ose' of disclosing my inven tion I have illustrated in the accompanying drawing in a, simplified and diagrammatic way one of the various forms which the devices e'mbodying; my invention may take, this illustration being selected more with a View to make it easy to understand the con struction, operation and characteristic fea turcs of a system embodying my invention, rather than with a view of showing the exact construction of parts preferably used in practice.

In describing the present invention in detail, reference will be madeto the accompany drawing,- in which? Figure 1 shows digrammatically one arrangement of trackway circuits which may be used in connection with the train control system embodying this invention;

Fig. 2 shows in a digrammatic and conventional manner one form of car-carried apparatus embodying the present invention;

Fig. is a plan view illustrating a construction for preventing the track rails of the crossing influencing the car-carried element; and

Fig. 4 is a vertical section taken on the line 44 in Fig. 3, as viewed in the direction of the arrows. V

This is a division of my prior application, Serial No. 287,132, for automatic train control system, filed April 3, 1919.

In de scrihingthe present invention, one form of inert track element will be described connection with a well-known arrangement of track circuits and control devices for controlling the actuation of said track element.

The trackway element T consists esseni 6.0 ti ally of a U-shaped core or oke 45, having pole pieces 46 and two coils or windings 47 wound on the yoke below the polepieces 46 in the same direction with respect to the core or in, other Words, so that the voltages due to a change of flux in the core will be cumulative. This yoke 45' and pole pieces 46 are made of iron or other n'iagnetic material, solid or laminated as conditions require. The pole pieces 46 are preferably disposed on the level, or just above the top of the heads of the track rails, so as to be as close as possible to the car-carried element and yet be out of the way of all parts of the rolling stock. The trackway element T is given diflerent controlling conditions. that is, is rendered capable of influencing or not influencing the carcarried element on a passing vehicle, by putting the coils 47. in an open circuit or in-a decnergized closed circuit of preferably low resistance. \Vhilc the circuit of the coils 47 may be controlled in any suitable way. I have illustrated in Fig. 1 one form of trackway circuits suitable for. governing the controlling condition of the tracltway element T in accordance with traffic conditions.

Referring to Fig. 1. the track rails 48 are divided by insulated joints 49 into blocks in the usual way, one block B with the adjacent ends of two other blocks A and being shown. The parts and circuits associated with the various blocks A, B and( are the same, and for convenience will be given like reference characters with distinctive exponents. Each of the blocks is provided with a track battery and a track relay 50, the same as the ordinary block signaling systems. Since my system of automatic train control is preferably used in connection with the usual fixed signals of the well-known automatic block signal system, such signals are indicated convention'- ally in Fig. 1; but the circuits and devices for controlling the indications and aspects of these fixed signals, being well-known in the art. have not been illustrated in order to avoid unnecessary complication.

At a suitable distance in the rear of the pair of insulated joints 49 at the entrance of each block is located the trackw: element T (the normal diicction of tra c being from left to right, as indicated by the arrow); and the circuit for the coils 47 of said traclnvay element is controlled by the contact finger or armature of a line relay 5]., the controlling circuit of which includes front contacts of the track relays of the corresponding block and the next block in advance. For example, the line relay 51 controlling tracluvay element T at the entrance of the block B is energized when neither the block B nor the block C is occupied, but is deenergized to open the circuit for the coils 47 when either of said blocks B or (7 is occupied.

The particular form of trackway circuits shown in Fig. 1 is merely illustrative of the manner in which. the trackway elements of my system are controlled in order to transinit a cautionary impulse at each caution signal, and not transmit such a cautionary impulse at a clear signal. Obviously, various vmodifications and alterations may be made in the particular traclrway circuits illustrated, it being evident that various expedients may be employed to assure the opening or closing of the circuit for the coils 47 of the trackway element T at signaling points, depending upon trafiic conditions in advance. Generally stated, the characteristic feature of the traclrway circuits employed in my system of train control is that the coils 17 of the trackway element are in closed circuit at a clear signal, but are open-circuited at a caution signal. In the trackway' circuits shown in Fig. 1, the coils ll" of the trackway element are likewise open-circuited at a stop or danger signal, but this is not compulsory.

The car-carried element suitable for cooperating with the trackway element T may take various forms, only one of'which has been shown. In the construction shown in Fig. 2, the car-carried element L comprises an invert-ed U-shaped core or yoke 52, of solid or laminated iron or steel, and is formed with. pole pieces 53, which are arranged to pass over the pole pieces 46 of the trackway element T. The air gap between the pole pieces 53 and l6 is preferably as short as practical working conditions will permit. l find that this air gap may be as long as four inches or more and still result in the transmission of the desired impulse, the size of theparts and the wind ings being, of course, properly proportioned. On one of the legs of the yoke 52 is Wound a coil 54, conveniently termed the energizing or field coil; and is energized by current from a battery 55 on the vehicle which flows through a continuously closed circuit. This circuit may be readily traced on the drawing and includes a relay 56, conveniently termed the check relay, which is of any suitable or well-known construction capable of dropping its armature 57 upon a predetermined reduction in the amount of current flowing through it.

Surrounding the other leg of the yoke 52 of the car-carried element L, is a coil or winding 58, conveniently termed the secondary or inducing coil. This secondary coil 58 is connected in a normally closed circuit which includes a battery 59 and the winding 61 of acontrol relay R provided with a contact operating element 60. This control relay R is of any suitable type capable of opening its contacts upon either an increase or a decrease in the normal current for which it is adjusted.

One form of construction of the control relay R comprises a coil 61 adapted to energize and attract a bar-armature or operating element 60, which is pivotally supported and-provided on its opposite end with a striking piece 70 of insulating material, and is disposed between contact springs '71 and 71 which normally bear against contact points 72. d hcn the n'iagnet 61 of the relay is energized by a normal current, the spring (56 is adjusted so that the contact springs 71 and 71 are both in contact with their respective contact points 72, the armature 60 being in a balanced position. The striking piece preferably made slightly shorter than the space between the contact springs 71 and F1 in order that the ari'nature 60 may have a slight movement from its middle balanced position before acting against said contact springs. It will be evident that a decrease in the normal current through the magnet 61 will permit the spring 66 to over-balance the attraction of the armature 60, thus separating the bottom contact spring "('1 from its contact point 72. If the current through the magnet 61 is increased above that normally flowing, and for which the relay is adjusted, the attraction of the armature 6O over-balances the opposition of the spring 66, thereby separating the other cooperating contacts 71 and 72. The circuit controlled by the relay R passes from one contact spring 71 through the contact points 72 to the other contact spring 71 as indicated. Thus, whenever, the current for which the relay is adjusted is either increased or decreased, the circuit controlled by the relay will be opened.

The car-carried apparatus of the present invention, as illustrated in Fig. 2, includes a suitable electro-pneumatic valve E. P. V. of the normally energized type which, if momentarily deenergized, will remain in its deenergized position until certain pressure changes have been effected, that is, until main reservoir pressure applied to the pipe MR is reduced a certain amount below the normal value. This device-E. P. V. may vent the brake pipe directly, or may cause an automatic application in any other suitable manner, as desired. The electro-pneun'iatic valve E. P. V. is normally energized through the following circuit :Starting at battery 74:, wire 75, contacts 71 72 and 71, wire 76, front contact 57 of the check relay 56, wire 77, winding of the E. l V., wire 78 back to the battery 7 .11. It should be noted that a slight decrease in current in the check relay 56, or a slight increase or decrease in the current flowing through the control relay R, will open this circuit and deenergize this E. P. V.

The operation of my inductive device for transmitting impulses from the track to a passing vehicle, according to the construction shown in Figs. 1 and 2, is as follows Under dangerous traflic conditions, that is, when the cautionary impulse should be transmitted, the line relay 51 is deenergized,

as previously explained, and the coils 47 of the trackway element are open-circuited. hen the car-carried element L approaches and comes directlyover the track element T,

liythe reluctance ,of the magnetic circuit through the yoke 52 of the car-carried element is greatly decreased, by reason of the fact that the trackway element affords a .lnagnetic bridge for conducting flux between the pole pieces 53 of said yoke. Consequently, the, flux through the legs of the yoke 52, and likewise through the inducing 'or secondary coil 58, normally produced by the field or energizing coil 54, is greatly and rapidly increased. This change in the flux through the secondary coil 58 produces an induced voltage in said. coil. As the yoke 52 of the car-carried element L recedes from the trackway element L, the flux through said yoke andthe secondary coil 58. is decreased, thereby inducing a voltage of opposite polarity. Thus, the voltage induced in the secondary coil 58 opposes or adds to the voltage of the battery 59, and thus changes the current normally flowing through the windings and the control relay R, thereby interrupting the circuit for energizing the E. P. V. and causing the train control apparatus to operate in the manner previously described. It is found in practice that the current induced in the secondary coil 58 during the passage of the car-carried element over the trackway element, is in effect a single cycle of alternating current, although the shape of the voltage and current waves are somewhat distorted. This reversal in polarity in the induced current also serves, it is believed, to assure the proper operation of the relay R, since the alternation in polarity causes an alternate increase and decrease in the currentnormally flowing in said relay which will open at least one of the pairs of contacts.

Under clear trafiic conditions, that is, when the vehicle is passing a clear signal, the coils 47 of the trackway element T are in a deenergized closed circuit of low resistance, thus providing a number of shortcircuited turns around each leg of the yoke 45 of said t-rackway element. When the carcarried element L passes over a tr'ackway element T having its coils 47 in closed circuit, it is found in practice that the flux throughthe secondary coil 58 of the carcarried element Ii is not materially altered; and consequently, current sufficient to cause operation of the control relay R is not induced. I attribute this action to the opposition or bucking action of the current inducedin the closed-circuited coils 47 of the trackway'element T, which prevents material change in the flux through the yoke 52 of the car-carried element.

It should be noted that the passage of the car element over a track element T, have ing its coils 47 open-circuited, decreases the reluctance of the magnetic circuit including these elements, which not only causes an increase of the total flux passing through the primary coil 54, but also causes an additional flux to pass through the sccondar coil 58 due to the diversion of said additional flux from leakage paths.

It should be borne in mind that the induction of a voltage in the secondary coil 58, is dependent on the rate of change of flux and not on the total flux passing through or linking this coil; and if. the rate of change of this flux, due to passage over crossing rails and the like, can be made low even for high vehicle speed, the transmission of false influences may be eliminated.

In Figs. 3 and 4 has been illustrated one method of reducing the rate of change of flux linking the secondary coil 58 when passing over extraneous magnetic bodies, such as crossing rails. In this construction bodies or masses of iron 91, with very gradually sloping ends, lead up to the track rails of the crossing, extend between said track rails at substantially uniform. height and then slope downward again gradually. These masses of iron 91 are disposed between the track rails in position so that the pole pieces 53 of the car-carried element pass over-them. The slope or inclination of the end portions of these bodies of iron is made so gradual that the change in flux through the yoke 52 of the car-carried element is likewise so gradual that not enough current is induced in the secondary coil 58 of said car-carried element, to cause operation of the control relay R.

It should be noted that the operation of the system is dependent upon the functioning of devices which have well recognized dependability. The reliable performance of track circuits and various other parts of automatic block si naling systems has been thoroughly established by long trial and experience, and the influence transmitting means and automatic train control apparatus of my system likewise consists of simple devices capable of accurate performance. Thus. without undue complication and expensive apparatus, I have provided a system in accordance with my invention which will obviate, to a large extent, if not entirely, the occurrence of accidents upon railways and one that will be operated only by track elements when they are in their active condition.

In disclosing my invention I have selected simplified forms of construction, it bein understood that various amplifications and modifications in accordance with goods design and engineering practice would be made in the specific construction shown and described when putting my invention to practical use. For instance, the car-carried elenaeasee 1 ment L would be firmly secured to some appropriate part of the frame or running gear of the locomotive, motor car or other railway vehicle, and would be placed in a suitable casing to protect it from the weather.

The particular location and manner of supporting this car-carried element would vary upon different equipments, but in all cases an ample clearance of four or more inches above the level of the tops ot the track rails could be readily provided, so that the car-carried element would not be struck or injured by the track rails at crossings, and the like, or by other similar projections usually encountered along railways. It will be evident that the distance of the car-carried element above the track rails will vary as the wheels of the vehicle wear down, or are replaced by new wheels; and l contemplate the provision of suitable means for adjusting the carrarried element vertically to compensate for such variations.

1 he trackway element is fastened securely in any appropriate manner to the ties of the track, either between or outside of the track rails according to which arrangement is best suited to the conditions of the particular installation, and this trackway element would be preferably housed and protected against dragging objects on passing trains by a planking or housing of wood, or some non-magnetic material. The trackway element may be located at any desired point along the track where it is required to trans mit a cautionary impulse to passing vehicles, and may be located at the approach to sharp curves, or other fixed hazards, as well as adjacent to the fixed signals of the block signaling system.

With the arrangement of trackway circuits shown in Fig. 1, the trackway element may be located at any point with reference to the entrance of a block, providing it is in the rear of the insulated joints at the entrance of the block, so that the vehicle will not stop itself by entering the block and putting the trackway element in its caution controlling condition. It will be evident, however, that if a different arrangement of trackway circuits is used, in which the trackway element at the entrance to a block is not controlled by the track relay of that block, the various trackway elements may be placed in advance of the fixed signals it circumstances make it desirable to do so. The con trol relay R and the E. P. V. would be placed in practice in a suitable casing or cabinet on the vehicle and protected from jar and vibration by spring supports, or the like.

The various parts of the system may be sealed or locked to prevent unauthorized or malicious tan'ipering with them; and recorders and other well-known devices may be used in connection with the system to check up the care and vigilence used by the engieign magnetic bodies constructed so as to neer. in short. various additions and Hindi tications, obvious to those sliilled in the art, may he made in the particular construction shown and described without departing from my invention; and I desire to have it understood that the specific cons uctions and arrangement of parts and circuits shown and described are merely illustrative of my invention, and do not exhaust the various modifications of the idea of means constituting my invention.

What l claim new and desire to secure by Letters Patent ot the United States, is

1. in an automatic train control system, the combination with a car-carried impulse device including a partial magnetic circuit and control means operable upon a quick change in reluctance of said magnetic circuit, cit magnetic bodies associated with the track rails of crossings and other foreign magnetic objects along the track for causing a gradual change in the reluctance of the magnetic circuit of the car-carried element on a passing vehicle.

2. In combination with an automatic train control system of the type in which control influences are transmitted to a moving vehicle inductively by the cooperation of a oar-carried impulse receiving element and a trackway element, the trackway ele ment when in its etl'ective condition causing an abrupt change of reluctance of a magnetic circuit including said car element upon passage of said oar element by said trackway element, and means for prevent ing crossing rails and the like from causing such an abrupt change comprising sloping approaches of magnetic material adjacent such crossing rails, whereby a gradual change of reluctance is effected.

A train control system comprising, a car-carried influence receiving means including means for producing a flux and an influence receiving coil, oi": traclzway devices for transmitting a control influence by causing a sudden change of flux through said influence receiving coil upon passage of said car-carried means by a traclrway device, and rail interference prevention means associated with crossing rails and the like, said interference prevention means and said crossing rails jointly causing a gradual increase of firm, a constant maintenance of flux and then a gradual decrease of flux as said car-carried means passes by such crossing rails, whereby no control influence will be transmitted by such crossing rails.

4. In a device for preventing the trans mission of inductive control influences in automatic train control systems, the combination with the usual trackway having foreign magnetic bodies, such as crossing rails associated therewith, and approaches of magnetic material associated with said forcause agradual change of flux in a oar-car- 'ried' device as it approaches such foreign magnetic body.

A train control system comprising; c-arl 'cairried apparatus including, a yoke of magnetic material having depending legs, a: flux producing coil on one leg and an influence receiving coil on another leg, electro-responsive means governed by said influence r eceiving coil, and ineans l'ocaied adjacent to foreign magnetic bodies along thetrackway to cause a gradual change of flux through said influence receiving coil instead ofua rapid change-of flux Whensaid car-carried "apparatus passes by such foreign magnetic bodies, thereby preventing said elec-tro-responsive device from bein; actuated.

6. Rail interference preventive means comprising, approaches of magnetic mate rial located adjacent to foreign magnetic bodies along, the traclnvay, said approaches being constructed so that the magnetic effect produced by said foreign magnetic bodies and said approaches upon suitable car-carried apparatus is very gradual and inefl'ective to actuate said apparatus.

In testimony whereof T hereby aiiix my signature.

VIN-THROP K. HOWE. 

